JP2550036Y2 - Terminal structure of high resistance measuring device - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a terminal structure of a high-resistance measuring device, and more particularly, to a circuit connection that can be changed depending on whether or not a high-resistance to be measured (hereinafter referred to as a DUT) is grounded. The present invention relates to the above-mentioned terminal structure.

[0002]

2. Description of the Related Art Generally, when measuring the resistance value of a high-resistance DUT using a measuring device such as an insulation resistance meter, it is necessary to change the circuit connection of the measuring device depending on whether or not the DUT is grounded. An example of a conventional terminal structure for such a change in circuit connection will be described with reference to FIGS. FIG.
FIG. 5 shows a triaxial connector terminal 21, a ground terminal 22, a guard terminal 23, and a high-voltage output terminal 24. The terminals 22, 23, and 24 constitute a binding post group 20. These terminals are
It is provided on a metal chassis 10 of the measuring device. As shown in FIG. 5, a high-resistance DUT 30 (covered by the conductive jacket 13) is connected to the triaxial connector terminal 21 via a triaxial coaxial cable 25.
The ground terminal 22 is grounded via the chassis 10 of the measuring device. In FIG. 5, a conductor (hereinafter, referred to as an intermediate conductor) 25 ′ located in the middle of the triaxial coaxial cable 25 is indicated by a broken line. The guard terminal 23
The output terminal 24 is connected to a first terminal 16a of a high-voltage source 16 also built in the chassis 10, and the output terminal 24 is connected to a first terminal 16a of an ammeter (picoamp meter) 15 built in the chassis 10.

As shown in FIG. 6, the terminal 22 and the terminal 23 or the terminal 23 and the terminal 24 are formed of a metal having an oval-shaped hole 26 and a horn-like portion 27 having a diagonally protruding shape in which half of the oval-shaped hole is missing. They are connected by a shorting bar 28 made of one piece. The oval-shaped hole 26 is connected to the terminal 23, and the connection of the horn 27 is changed to the terminal 22 or the terminal 24 as necessary (FIG. 5 shows a case where the connection is made to the terminal 24). However, in the conventional binding post group 20 shown in FIG. 4, the shorting bar 28 is always exposed between the terminals 22 and 23 or between the terminals 23 and 24. May be touched due to caution. The voltage of the high voltage source 16 appearing on the shorting bar 28 is several hundreds to several thousand volts, which may lead to a fatal accident, which is extremely dangerous. The shorting bar 28 constitutes a part of the circuit of the ammeter 15,
This causes an error in the measured value due to coupling with the external electromagnetic field, and there is also a problem that accurate measurement becomes difficult. Further, when the terminals 22 to 24 of the binding post group 20 having such a configuration are used, another lead or the like can be connected to the terminal to which the shorting bar 28 is connected, so that a measurement lead connection error occurs. There is also a risk. Such a connection error has a high risk similarly to the above, and is not preferable in terms of circuit protection.

[0004]

SUMMARY OF THE INVENTION The present invention has been proposed in order to solve the above-mentioned problems, and there is no danger that an operator touches a high-voltage portion of a terminal of a measuring device, and measurement by an external electromagnetic field is performed. An object of the present invention is to provide a terminal structure of a high-resistance measuring device that significantly reduces the occurrence of errors.

[0005]

SUMMARY OF THE INVENTION In the terminal structure of the high resistance measuring device of the present invention, an ammeter and a high voltage source are built in a conductive chassis of the device, and a coaxial connector terminal (hereinafter simply referred to as a "connector terminal") is provided in the chassis. ), A ground terminal, a guard terminal, and a high-voltage output terminal. The external conductors of the ground terminal, guard terminal, and output terminal are connected to the chassis and have the same potential as the chassis.
At the same time, the center conductor of the ground terminal is
The center conductor of the guard terminal is connected to the first terminal of the ammeter, and the center conductor of the output terminal is connected to the first terminal of the high voltage source. These ground terminals, guard terminals, and output terminals are female, and there is no possibility that the operator will be exposed to high voltage due to errors or the like. The chassis is provided with an input terminal (this terminal is also a connector terminal) connected to the high-resistance DUT via a coaxial cable (usually a triaxial coaxial cable), in addition to the above three terminals.

In the present invention, the shorting member is provided with a pair of male connector terminals. The shorting member can be configured by, for example, providing a pair of male connector terminals on a conductive jacket, or can be configured by a coaxial cable having male connector terminals at both ends. In the former case, each outer conductor of the connector terminal is connected to the jacket of the shorting member, and each inner conductor is short-circuited by the shorting bar. In this case, the distance between the ground terminal and the guard terminal and the distance between the output terminal and the guard terminal of the chassis of the measuring device are provided so as to be equal to the distance between the pair of connector terminals provided on the shorting member. . When the shorting member is made of a coaxial cable,
It goes without saying that the distance between the ground terminal, the guard terminal and the output terminal can be set arbitrarily.

In the present invention, B is used as a connector terminal.
The NC type is used. The operator selects either the ground terminal / guard terminal pair or the output terminal / guard terminal pair and short-circuits. Thus, a measurement circuit for measuring high resistance is configured. For example, when measuring the resistance value of the non-grounded high-resistance DUT using the terminal structure of the high-resistance measuring device of the present invention, the grounding terminal and the guard terminal are short-circuited by the shorting member.
The center conductor of the coaxial cable drawn from the input terminal is connected to one terminal of the DUT. Therefore,
High voltage source → output terminal → DUT → above input terminal → ammeter →
The measurement current flows through the path of guard terminal → shorting member → ground terminal → ground. In this case, the outer conductor of the output terminal and the conductive jacket or the like in which the DUT is housed are connected via the outer conductor of the coaxial cable.

Further, when measuring the resistance value of a grounded high-resistance DUT, the output terminal and the guard terminal are short-circuited by the shorting member, and the input terminal is short-circuited as in the case where the DUT is not grounded. The center conductor of the drawn coaxial cable is connected to one terminal of the DUT. Therefore, high voltage source → output terminal → shorting member →
The measurement current flows through the path of guard terminal → ammeter → input terminal → DUT → ground. In this case, the ground terminal is open. A coaxial cable is used to ground the DUT, the DUT is connected to the center conductor of the coaxial cable, and a conductive jacket or the like in which the DUT is housed is connected to the outer conductor of the cable. Sufficient shielding is also provided for wires.

In any of the above cases, the external conductor of the input terminal is connected to a jacket or the like in which the high-resistance DUT is housed, and the internal conductor is connected to the other terminal of the DUT. Note that the input terminal is usually constituted by a triaxial connector terminal, and the intermediate conductor (the conductor located between the center conductor and the outer conductor) is set to the same potential as the power supply voltage, thereby improving measurement accuracy. .

As described above, in the terminal structure of the present invention, the ground terminal and the guard terminal and the output terminal are constituted by the female connector terminal, and the pair of the ground terminal and the guard terminal or the pair of the output terminal and the guard terminal is formed. Since short-circuiting is caused by the shorting member provided with the connector terminal, no high voltage is exposed, and all paths from the high-voltage source to the ground through the DUT, including between the terminals, are connected to the connector. Terminals, outer conductor of coaxial cable, chassis of measuring equipment, jacket of shorting member, DUT
Is shielded by a conductive jacket or the like that stores the Therefore, there is almost no possibility that the operator touches the high-voltage portion, and the possibility that a measurement error due to noise in the measurement current due to an external electromagnetic field is extremely small, thereby improving the measurement accuracy.

[0011]

In FIG. 1, a chassis 10 of an insulation resistance meter has an input terminal 1 composed of a male triaxial coaxial connector terminal, a ground terminal 2 composed of a female coaxial connector terminal, a guard terminal 3, The high voltage output terminals 4 are arranged in a line. The distance between the ground terminal 2 and the guard terminal 3 and the distance between the guard terminal 3 and the output terminal 4 are equal, and this distance is the same as the distance between the male coaxial connector terminals 6 and 7 of the shorting member 5 described later. You. Note that female terminals 2, 3, and 4 and male terminals 6,
As the connector type of No. 7, a BNC type connector is used.

An outer conductor outside the input terminal 1 is grounded (connected to the chassis 10 in FIGS. 2 and 3), and a center conductor is a second terminal of an ammeter (picoamp meter) 15 built in the chassis 10. 15b, and the middle conductor of the input terminal 1 is not shown in FIG.
(Indicated by a broken line in FIG. 3). Thus, the outer conductor outside the input terminal 1 is set to the same potential as the first terminal potential of the ammeter 15 (the voltage of the high voltage source 16). The input terminal 1 is connected to a high-resistance DUT 30 via a triaxial coaxial cable 25 to which a male triaxial connector terminal (not shown) is connected.
(See FIGS. 2 and 3).

The external conductors of the ground terminal 2, the guard terminal 3 and the output terminal 4 are the same as the external conductor of the input terminal 1.
The center conductor of the ground terminal 2 is connected to the chassis 10 (grounded via the outer conductor of the input terminal 1 in the figure), and the center conductor of the guard terminal 3 is connected to the above-described ammeter 15. The center terminal of the output terminal 4 is connected to the first terminal and the first terminal 16 a of the high voltage source 16. The shorting member 5 shown in FIG. 1 connects between the ground terminal 2 and the guard terminal 3 or between the output terminal 4 and the guard terminal 3. In FIG. 1, a pair of male connector terminals 6, 7 having an external conductor connected to the outer cover 8 are provided on a conductive outer cover (metal outer cover) 8 of the shorting member 5 . The center conductors of these male terminals 6 and 7 are short-circuited by a shorting bar 9. These male terminals 6, 7 can be fitted with the female terminals of the ground terminal 2, guard terminal 3, or output terminal 4, and the distance between the male terminals 6, 7 is, as described above, the ground terminal 2 and the guard. Between terminals 3, guard terminals 3
The distance is the same as the distance between the output terminals 4.

Next, an example of usage of the terminal structure will be described with reference to FIGS. FIG. 2 shows the ungrounded D
FIG. 3 shows a connection mode when measuring the UT 30 and a grounded DUT 30, respectively. In FIG.
The ground terminal 2 and the guard terminal 3 are short-circuited by the shorting member 5 . Thereby, the measurement current is changed from the high voltage source 16 → the output terminal 4 → the coaxial cable 11 → the DUT 30
(Coated with the conductive jacket 13) → Triaxial coaxial cable 25 → Input terminal 1 → Ammeter 15 → Guard terminal 3 → Shorting member 5 → Ground terminal 2
→ It flows along the chassis path.

In FIG. 3, the output terminal 4 and the guard terminal 3 are short-circuited by the shorting member 5 . The DUT 30 is grounded by a grounding coaxial cable 26. As a result, the measured current is changed from the high voltage source 16 to
Output terminal 4 → Guard terminal 3 → Ammeter 15 → Input terminal 1 →
The triaxial coaxial cable 25 → the DUT 30 → the coaxial cable 26 → flows through the ground. FIG. 2,
In FIG. 3, the middle conductor 25 'of the triaxial coaxial cable 25 is shown by a broken line, and the middle conductor 25' is shown.
Is the first of the ammeter 15 through the intermediate conductor of the ground terminal 1.
It is connected to terminal 15a.

As described above, by using the terminal structure of the present invention, the conventional shorting bar 28 (FIG. 6) is used.
) Can be very easily connected between terminals. In addition, the ground terminal 2, the guard terminal 3, and the output terminal 4 are composed of female connector terminals, and are used for shorting with a connector terminal between the ground terminal 2 and the guard terminal 3 and between the output terminal 4 and the guard terminal 3. Since the member 5 is short-circuited, the high voltage of the high voltage source 16 is not exposed, and from the high voltage source 16 to the ground through the DUT 30, including between the terminals 2, 3 and 4, 3. Are the connector terminals 1 to 4, the outer conductors of the coaxial cables 11 and 12, the measuring apparatus chassis 10, the jacket 8 of the shorting member 5 , the conductive jacket 13 for housing the DUT 30, and the ground for the DUT 30. Coaxial cable 26
Is shielded by an external conductor or the like. Therefore, the possibility that the operator touches the high voltage portion becomes extremely small, and the possibility that a measurement error occurs due to noise in the measurement current due to the external electromagnetic field becomes extremely small.
Furthermore, if the shorting member 5 is connected to the ground terminal 2, guard terminal 3, and output terminal 4, it is not possible to connect a measuring cable or the like to one terminal as in the prior art, so carelessly. As a result, it is possible to prevent an artificial connection error due to the above-mentioned situation, and also to protect the measuring device.

In the above embodiment, the shorting member 5 is formed of the conductive jacket 8. However, the shorting member 5 is provided with a coaxial cable having male connector terminals at both ends. Can also be configured. In this case, the distance between the ground terminal 2, the guard terminal 3, and the output terminal 4 provided on the chassis 10 can be arbitrarily set.

[0018]

As described above, according to the terminal structure of the present invention, the following effects can be obtained. (1) For example, connection between terminals can be extremely easily performed as compared with a conventional binding post terminal structure in an insulation resistance meter. (2) It is possible to provide a terminal structure of a measuring device which is excellent in safety and minimizes a measurement error due to an external electromagnetic field. (3) An artificial connection error can be prevented beforehand,
The measurement device circuit can also be protected. (4) By using a coaxial cable as the shorting bar, the shorting member can be constituted by a non-conductive jacket, and the terminal structure can be realized at low cost.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing one embodiment of a terminal structure of the present invention.

FIG. 2 is an explanatory diagram showing a mode of measuring a high resistance that is not grounded using the terminal structure of FIG. 1;

FIG. 3 is an explanatory diagram showing a mode of measuring a grounded high resistance using the terminal structure of FIG. 1;

FIG. 4 is a diagram showing a terminal structure of a conventional measuring device.

FIG. 5 is an explanatory diagram showing a case where high resistance is measured using a conventional terminal structure.

FIG. 6 is an explanatory view showing a conventional shorting bar.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Input terminal 2 Ground terminal 3 Guard terminal 4 High voltage output terminal 5 Shorting member 6,7 Connector terminal of shorting member 8 Shorting member jacket 9 Shorting bar 10 Chassis of measuring device 15 Ammeter 16 High voltage source

Claims (1)

(57) [Scope of request for utility model registration] 1. A shorting member provided with a pair of male coaxial connector terminals having an internal conductor short-circuited by a shorting bar, an ammeter and a high voltage source, and a coaxial cable having a high resistance to be measured. A measuring device having an input terminal connected through a female terminal, a ground terminal, a guard terminal, and a high-voltage output terminal formed by a female coaxial connector terminal that can be fitted to the coaxial connector terminal of the shorting member. Provided, a center conductor of the ground terminal is connected to a chassis of the measuring device, a center conductor of the guard terminal is connected to the ammeter, and a center conductor of the output terminal is connected to the high-voltage source. A measuring device in which each external conductor of a ground terminal, a guard terminal and an output terminal is connected to the chassis. Terminal structure of fixed device.